Container manufacturers typically subject their containers to leak testing for quality control purposes. In this regard, the automated testing of containers generally by pressurizing the interior volume of the container and detecting any pressure decay (which decay would be indicative of a defective container--e.g., a hole) is well known, as evidenced by U.S. Pat. No. 3,307,390 to Behrens et al. Problems are encountered, however, when attempts are made to employ prior techniques to pressure-test rimmed containers having flexible side walls.
In this regard, flexible walled containers which are supported by a rim structure, such as the deep drawn containers manufactured in accordance with U.S. Pat. Nos. 4,836,764; 4,997,691 and 5,091,231 each issued to Keith Parkinson (the entire content of each being expressly incorporated hereinto by reference), cannot be reliably sealed along their rim due to its relatively small size and possible uneven surface configuration. As a result, the container may not be capable of being pressurized using conventional techniques.
Furthermore, the flexible side wall of the containers makes it difficult to eject the containers in the event a leak is detected. That is, the typical flexible walled container is usually supported by the container rim in a tray structure with the flexible side wall dependently extending through the supporting tray. This form of manufacturing arrangement makes it difficult to extract the defective container individually from the tray without disturbing neighboring non-defective containers.
What has been needed in this art, therefore, are apparatus and methods whereby flexible-walled containers may be pressure-tested for purposes of quality control with any detected defective containers being individually ejected following such pressure testing. It is towards providing such apparatus and methods that the present invention is directed.
The present invention therefore generally includes apparatus and methods whereby flexible walled containers may be automatically pressure tested at a pressure testing station for the purpose of determining the presence of defective containers. Detected defective containers may thereafter be transported to an ejector station and ejected physically from their respective supporting tray. In such a manner, any detected defective containers may be removed from the process line prior to final processing (e.g., packing, palletizing, shipping and/or subsequent handling).
Most preferably, the pressure testing station is provided with an array of pressure testing heads which are moveable reciprocally towards and away from the containers while supported in their tray. Each of the pressure testing heads thus makes sealing contact with the rim of an individual respective one of the containers supported in the tray. A lower support structure is most preferably moved into contact with the tray simultaneously with the movement of the testing heads so as to counteract the force of the testing heads against the tray and thereby prevent the tray from bowing in the cross-machine direction.
The ejector station is provided with an array of ejector assemblies equal in number to the number of containers supported on a tray and oriented at an angle relative to a vertical cross-machine plane. If a container is determined to be defective (i.e., will not maintain a predetermined pressure condition when a pressurizing fluid, such as pressurized air, is introduced into the container at the pressure testing station), a controller will issue a signal corresponding to that one of the ejector assemblies which is in registry with the detected defective container. Selective activation of that one ejector assembly will therefore cause an ejector foot to come into contact with the side wall of the defective container thereby forcing the container downwardly through the tray.
In this regard, the ejector foot asymmetrically contacts the container side wall when it is in its extended position due to the angular orientation of the ejector assemblies. This asymmetric contact therefore imparts an asymmetric downward force on the container rim in a region generally opposite the contact region between the ejector foot and the container side wall, thereby causing the container rim to collapse inwardly. As a result, the entire container is capable of being pushed physically through the tray.
These and other aspects and advantages of the present invention will become more clear from the following detailed description of the preferred exemplary embodiments thereof which follow.